My friends boyfriend cheats on her and she wont leave him?

She's got big problems. Girls who stay with bums do so because they're afraid no one else will ever ask them out again. Stupid stubbornness, poor self-image, low self-worth, fear & mediocrity. Those are her problems. She settles for crap because she's not willing to endure the work it takes to meet normal people. See if you can introduce her to a nice guy you know and can vouch for. Bring her around relationships that are healthy so she can see normalness. Show her those terrible Lifetime movies about the cheating spouse/boyfriend & tell her her situation will only get worse & she'll end up as the desperate wife who drives her car into a house. You need to be blunt and direct. She needs to dump him and gain the upper hand on her sanity.